The band said Friday on their website Deryck Whibley was attacked late Friday night. They posted on their Twitter account that Whibley was attacked in a bar by three unknown people and Japanese police are investigating.

The band had two remaining tour dates scheduled in Osaka, Japan, before closing out the summer with shows in the U.S. and Europe.

The alleged attack follows Sum 41's cancellation of several Warped Tour dates in the U.S. because Whibley had come down with a serious case of bronchitis.

Whibley, 30, was married to fellow Canadian pop star Avril Lavigne but the couple announced their separation last September.